Smoking has been a common pastime in many cultures for probably hundreds of years. Conventionally, smoking has been performed using various devices that involve the combustion of tobacco, such as cigarettes, cigars and pipes. The combustion of tobacco produces smoke which is transmitted to a user. In the case of pipes and cigars, the smoke is typically not inhaled by the user, but in the case of cigarettes, the smoke is inhaled. The flavors included within the smoke caused by combusting tobacco produce a pleasurable effect in the user. Various attempts have been made to produce a smoking device that does not rely on tobacco. Many of these devices are adapted to look like conventional smoking articles such as cigarettes. One such example is the simulated smoking device taught in U.S. Pat. No. 4,284,089 to Ray. The simulated smoking device includes a container having an internal source of nicotine. The source of nicotine does not completely fill the air passageway of the container. Thus, a constricted region of the air passageway is created within the source of nicotine. Upon the application of suction by a user at one end of the container, pressure is reduced in the constricted portion of the passageway which causes nicotine to be released from the source of nicotine and enter the passing air.
In another device, shown in European Patent No. 0 198 268 to Ellis et al., a smoking device is disclosed which includes a housing for receiving a conventional cigarette at one end and a mouthpiece at the other end for delivering cigarette smoke to a user. Located between the mouthpiece and the conventional cigarette is a nicotine dispensing unit.
Still other devices have been developed as an alternative to conventional smoking articles. These articles generally attempt to simulate conventional cigarettes without the combustion of tobacco products. For example, many devices include an internal aerosol forming material that is heated by an internal heating element. The heating stimulates the production of a flavorful aerosol for delivery to a user of the device. The internal heating element has conventionally been either a carbonaceous fuel element, or an electrochemical heat source such as combinations of metal oxide, anhydrous metal sulfide, metal sulfate, inorganic salt and a sugar which generate heat on contact with water. In these devices, the cigarette is not capable of being reused. Once the carbonaceous fuel element is lit it continues to burn unattended until all the fuel in the element is consumed. The lit fuel element is very difficult to extinguish, either with water or other means for extinguishment. If based on an electrochemical reaction, difficulty is also encountered in stopping the reaction which only terminates when all the reactants are consumed. Other devices include an electrical heating element for stimulating an aerosol forming substance. Although these are capable of being turned off between puffs, the electrical heating element requires a battery which is clumsy.
It would be desirable to provide an article that closely simulates a conventional cigarette but does not require the combustion of tobacco and can be reused as well. A need also exists for an article where the timing for individual puffs is determined by the user, and not controlled by the time or type of reaction. It would further be desirable to minimize, if not eliminate, combustion by-products of the substrate while heating air is drawn through the device.